The present invention broadly relates to a new and improved construction of a winding machine for filament packages which is particularly, but not exclusively, related to further developments of the winder disclosed in European published Patent Application No. 82107022.4, published under the publication No. 73,930 on Mar. 16, 1983, the full disclosure of which is hereby incorporated in the present application by reference. This European patent application corresponds to the aforementioned U.S. patent application Ser. Nos. 412,014, 411,701 and 411,908.
Generally speaking, the winding machine of the present invention serves for winding thread, especially synthetic plastic filament and comprises a friction drive member having a longitudinal axis and rotatable about this longitudinal axis. The winding machine also comprises a first chuck having a longitudinal axis and movable along a first predetermined path from a rest position thereof to a winding position thereof in which the first chuck is driven into rotation about the longitudinal axis thereof by the friction drive member, the first chuck being returnable to its rest position by movement along the first path. The winding machine also comprises a second chuck having a longitudinal axis and movable along a second predetermined path from a rest position thereof to a winding position thereof in which the second chuck is driven into rotation about the longitudinal axis thereof by the friction drive member, the second chuck being returnable to its rest position by movement along the second path. The first path is disposed above the second path.
Certain developments of the winder disclosed in the aforementioned European published Patent Application have been described in the likewise aforementioned U.S. application Ser. No. 597,373, filed Apr. 6, 1984, and the full disclosure of that U.S. application is also incorporated in the present application by reference.
Briefly, the winding machine disclosed in each of the aforementioned European published Patent Application, published under the publication No. 73,930 and U.S. application Ser. No. 597,373 comprises first and second chucks movable along respective paths from respective rest positions into operative relationship with a friction drive member. That chuck in operative relationship with the friction drive member is driven thereby into rotation about its longitudinal chuck axis so that a thread, usually a synthetic plastic filament, can be formed into a package by winding in a predetermined pattern around the chuck. Such a winding machine is referred to hereinafter as a "winder of the type described."
The chucks are moved successively into operative relationship with the friction drive member and a thread continuously delivered to the winding machine can be transferred from an "outgoing" to an "incoming" chuck. Thus, the continuously delivered thread is continuously taken up into packages forming on one or the other of the two chucks. While a package is forming on one chuck, a so-called "doffing operation" can be carried out on the other chuck while the latter is held in its rest or idle position. This doffing operation comprises the steps of removing the package formed on the relevant chuck during the immediately preceding winding operation, and replacing such package with an empty bobbin tube upon which the next package can be formed.
For convenience of description, reference will usually be made to only one package per chuck, however, as is now well known in the filament winding art, each chuck normally carries a plurality of (usually up to 8) bobbin tubes during any given winding operation and a corresponding number of thread packages are formed simultaneously. The principles described herein also apply to such multi-package winding systems.
In each of the embodiments of the prior art constructions, the chucks are disposed one above the other so that they approach their operative relationships with the friction drive member from opposite sides of a horizontal plane. In such an arrangement, a "working zone" of the winding machine can be at least approximately defined; the rest or idle position of the upper chuck lies above this working zone, the rest or idle position of the lower chuck lies below the working zone, and the friction drive member is located to one side of the working zone. Each chuck moves through the working zone in moving from its respective rest or idle position into operative relationship with the friction drive member, and also during the return movement towards the respective rest or idle position during build-up of a package between the chuck and the friction drive member.
Problems can arise since, while a chuck with a completed package is braked to a standstill, a thread tail on the package is thrown radially outwards by centrifugal force into the working zone. Also, when the upper chuck is stationary, a thread tail from a completed package carried by this chuck can hang down into the working zone. The thread tail may then become entangled in the newly forming package on the other chuck or in thread catching means on the chuck itself. This can represent a safety hazard for a person performing a doffing operation.
The problems presented by thread tails extending from completed packages are well known in the filament winding art, and various solutions have been put forward. In particular, U.S. Pat. Nos. 3,165,274, granted Jan. 12, 1965, and 3,409,238, granted Nov. 5, 1968, describe shields which can be interposed between a completed package and the friction drive member in order to prevent wrapping of a thread tail on the friction drive member. An alternative solution, involving a pivotable thread retainer, has been shown in the U.S. Pat. No. 4,327,872, granted May 4, 1982.